This hemoglobin is abnormal and causes blood cells to take on a sickle shape. Sickle cell is a result of a mutation in the hemoglobin gene. Hemoglobin helps red blood cells bind to and transport oxygen to cells and tissues of the body. Normal red blood cells have a biconcave, disc-like shape and contain enormous amounts of a protein called hemoglobin. Sickle cell disorder results from the development of abnormally shaped red blood cells. An example of co-dominance is seen in individuals with the sickle cell trait. This results in a third phenotype in which more than one phenotype is observed.
In co-dominance relationships, neither allele is dominant, but both alleles for a specific trait are completely expressed. SCIEPRO/Science Photo Library/Getty Images This image shows a healthy red blood cell (left) and a sickle cell (right). This indicates that the allele for one phenotype is expressed slightly more than the allele for the other phenotype. For example, an individual with wavy hair may have more or fewer waves than another with wavy hair. In incomplete dominance, one characteristic may be slightly more observable than another for a given trait. The dominant curly characteristic is not fully expressed over the straight characteristic, producing the intermediate characteristic of wavy hair. An individual who is heterozygous for this trait will have wavy hair (Cc). Curly hair type (CC) is dominant to straight hair type (cc).
An example of incomplete dominance is seen in hair type inheritance. This results in a third phenotype in which the observed characteristics are a mixture of the dominant and recessive phenotypes. In incomplete dominance relationships, one allele for a specific trait is not completely dominant over the other allele. Heterozygous dominance relationships that are typically seen in animal cells include complete dominance, incomplete dominance, and co-dominance.Ĭurly hair type (CC) is dominant to straight hair type (cc). When the paired alleles for a trait are different or heterozygous, several possibilities may occur. When the allele pairs are the same, the genotype for that trait is identical and the phenotype or characteristic that is observed is determined by the homozygous alleles. Paired alleles can be homozygous (having identical alleles) or heterozygous (having different alleles) for a given trait. For each characteristic or trait, animal cells typically inherit two alleles. They are passed on from one generation to the next through sexual reproduction. The gene for a specific trait can exist in more than one form or allele. Genes are segments of DNA located on our chromosomes. As discovered by Gregor Mendel, traits are inherited by the transmission of genes from parents to their offspring. Have you ever wondered why you have that particular eye color or hair type? It's all due to gene transmission.
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